A COALITION government would spend $751.5 million over four years to help the rivers in the ailing Murray-Darling Basin.

The future of the Murray-Darling should not and cannot be a choice between the environment or agriculture,'' Opposition Leader Tony Abbott said near the mouth of the Murray River in South Australia today.

"We will end the delays, act on the concerns of basin communities and end the blatant politicking that has spoiled so many previous efforts at water reform.''

The coalition will also commit an additional $300 million to invest in rural water infrastructure.

Mr Abbott said that was a crucial step in saving water for the environment while keeping economic engines at the basin alive.

Yesterday, Labor committed an unknown amount of money to provide the rivers with all the water determined by the Murray-Darling Basin Authority.

How much water that will be won't be known until the authority releases a discussion paper following the August 21 poll.

The NFF welcomed the coalition announcement, especially the extra $300 million for on-farm works, and said it had "raised the bar" on water policy.

"This is a positive new investment in water-saving infrastructure in the Murray-Darling Basin,” NFF president David Crombie said. 

“The NFF has consistently called on the Government to accelerate delivery of water infrastructure projects to keep pace with its water buy-backs in the Basin. 

“The extra $300 million announced today is designed to forge a partnership between government and irrigators to improve water-use efficiency, return water savings to the environment and create jobs in regional areas. Expanding these vital upgrades is a positive, holistic approach. 

“Over the past two days, announcements by both major political camps have addressed several issues for farmers, communities and environmental needs in the Basin," Mr Crombie said.

"However, the Coalition has raised the bar by committing to ensuring balance in the new Basin Plan."

Mr Abbott said the coalition would release the draft basin plan within two weeks of coming to office and proceed with implementation without delay.

Irrigators, food producers and communities throughout the basin are crippled with the uncertainty of how much water they will each lose, he said.

Those most concerned about environmental assets also worry about whether the water will start flowing soon enough to rescue them, he added.

Labor immediately dismissed the coalition commitment, saying it was akin to taking a Berocca for a broken leg.

"The water that he is purchasing is only for one season,'' Water Minister Penny Wong told ABC Radio of Mr Abbott's announcement.

"What happens next season and the season after.''

Senator Wong said Labor had already bought one in every 20 litres of irrigation water used in the basin and by the end of its next term in government that would amount to one in seven litres.

"We are determined to do what the river needs,'' she said.

There was no shortage of willing sellers of water entitlements in the basin, Senator Wong said.

"To date our experience has been that more people ... than we have budgeted for, purchase.''

"Australians need food to eat, people in Adelaide need water to drink, the environment needs water to sustain it,'' Mr Abbott told reporters.

The coalition would kick-start its original plan for the basin that had "basically been stalled for three years'' following Labor's  2007 election win.

Mr Abbott said the coalition would spend $400 million on NSW's Menindee Lakes, a far cry from Labor's pledge of just $100 million.

The second important feature of the coalition plan was to get water "straight away'' into the Coorong near the mouth of the Murray River.

"We will buy 150 billion litres of water on the short-term water market,'' Mr Abbott said.

"One hundred billion of those litres will go into the Coorong.''

Mr Abbott said it would be the most significant inflow of fresh water in the wetlands in a decade.

"This is a good day for the people of Adelaide and everyone who wants to see comprehensive management of water in the Murray Darling-Basin,'' he said.

Mr Abbott said he expected the states to work with the federal government to save the basin.

"I'm confident the states would cooperate with an incoming coalition government,'' he said.

''(But) we won't cop procrastination from the states.

"We've had a hundred years of inaction on the Murray-Darling and if there is no action, yes, as a last resort, we would be prepared to go to a referendum.''

Opposition water spokesman Barnaby Joyce said the coalition plan was the culmination of a lot of hard work and visits to town in three states.

"We have put together a program of $400 million to help those towns that have been left behind,'' he told reporters.

"As Julia Gillard moves forward, she is leaving people behind everywhere.''

Senator Joyce said Labor paid $23.75 million for a property (Toorale Station near Bourke in north-western NSW) without inspection and without realising it didn't actually deliver water into the Darling (River).

"This is the sort of incompetence we expect from Labor,'' he said.